Display technologies have included television cathode ray tubes, plasma displays, and various forms of flat panel displays. Typical television cathode ray tube displays utilize an emissive coating, typically referred to as a “phosphor” on an interior, front surface, which is energized from a scanning electron beam, generally in a pattern referred to as a raster scan. Such television displays have a large, very deep form factor, making them unsuitable for many purposes.
Other displays frequently used for television, such as plasma displays, while having a comparatively flat form factor, involve a complex array of plasma cells containing a selected gas or gas mixture. Using row and column addressing to select a picture element (or pixel), as these cells are energized, the contained gas is ionized and emits ultraviolet radiation, causing the pixel or subpixel containing a corresponding color phosphor to emit light. Involving myriad gas-containing and phosphor-lined cells, these displays are complicated and expensive to manufacture, also making them unsuitable for many purposes.
Other newer display technologies, such as active and passive matrix liquid crystal displays (“LCDs”), also include such pixel addressability, namely, the capability of individually addressing a selected picture element. Such displays include a complex array of layers of transistors, LCDs, vertically polarizing filters, and horizontally polarizing filters. In such displays, there is often a light source which is always powered on and emitting light, with the light actually transmitted controlled by addressing particular LCDs within an LCD matrix. Such addressing, however, is accomplished through additional layers of transistors, which control the on and off state of a given pixel.
Currently, creation of such displays requires semiconductor fabrication techniques to create the controlling transistors, among other things. A wide variety of technologies are involved to fabricate the liquid crystal layer and various polarizing layers. LCD displays also are complicated and expensive to manufacture and, again, unsuitable for many purposes.
As a consequence, a need remains for a scalable electronic display, which may provide substantially larger form factors, suitable for applications such as outdoor signage. In addition, for various applications, such an electronic display should provide a printable surface, for direct application of an image to be illuminated. Such an electronic display should also provide for significant durability with a capability to withstand typical environmental conditions, especially for outdoor applications or other applications in environments having variable conditions.
A further need remains for a dynamic electronic display which provides for pixel addressability, for the display of dynamically changing information. Such a display further should be capable of fabrication using printing or coating technologies, rather than using complicated and expensive semiconductor fabrication techniques. Such a display should be capable of fabrication in a spectrum of sizes, from a size comparable to a mobile telephone display, to that of a billboard display (or larger). Such a display should also be robust and capable of operating under a wide variety of conditions.